Support for electrodes in vacuum vessels



April 18, 1933. I R. c; BERTHOLD ET AL I 1,

SUPPORT FOR ELECTRODES IN VACUUM VESSELS Filed May v1,, 1951 v j 2 J33,

M j P Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE RUDOLF GOTTFBIED BERTHOLD, OF BERLIN-SIEMENSSTADT, AND WALTER STOCK- MEYER, OF FINKENKBUG NEAR BERLIN, GERMANY, .ASSIGNORS T0 SIEMENS- SCHUCKERTWERKE AKTIENGESELLSCHAIT, OF BERLIN-SIEMENSSTADT, GERMANY,

A CORPORATION OF GERMANY SUPPORT FOR ELECTRODES IN VACUUM VESSELS Application filed May 1, 1931, Serial No. 534,242, and in Germany May 7, 1930.

Our invention relates to a support for electrodes in vacuum vessels, e. g. for filaments in electron tubes, for grids etc. When long hot wires or filaments are used in lamps, control valves, rectifying valves etc., it is necessary to provide the filament with intermediate supporting means in addition to the support they have at their ends, in order to prevent deformations due to the weight of the filaments or to electrostatic forces. The holders must be insulated from one another as well as from the partof the support carrying the current. For this reason, wires fused in glass, for instance in a similar manner as in normal incandescent lamps, are employed by the prior art as supports. In. cases where the insulating member is exposed to high temperatures, other substances, such as quartz, zirconium oxide, or any of the well known compounded refractory materials, such as porcelain are employed.

The known arrangements have, among others, the following drawbacks. Owing to their great brittleness, the insulating members are liable to crack or to be damaged under the influence of the strains caused by the heat or when the load is excessive. The known arrangements are bothersome to mount, particularly when several supports for filaments are to be fixed.

According to our invention, these disadvantages are avoided by making the stem serving as the support consist of a plurality of small insulating members placed the one upon the other, and by pressing these small insulating members together with resilient metal parts. The accompanying drawing illustrates by way of example, several forms of executing the present invention.

Fig. 1 shows in semi-diagrammatic form and in sectional elevation the filament supporting column built up of individual insulating blocks.

Figs. 2 and 2 show respectively in plan view and central vertical section one form of guiding the blocks,

Figs. 3 and 3 4 and 4 5 and 5 6 and 6; 7 and 7 show respectively in similar views modified forms of the manner of guiding the blocks and of attaching the filament i elements between each block, and

Figs. 10*, 10, 10 show three plan views of a modified form of block, showing the filament supportingarms in three dilferent relative angular positions.

As will be seen from Fig. 1, the novel support consists of small insulating blocks 1 laid one upon another, and arranged between guide rods 3. These guide rods connect by way of radial bar 6 the upper end of the filament with the supporting plate 7 of the column, which plate is in turn connected to the current inlead 7 The lower end of the filament is directly connected to inlead 7 The blocks are pressed together in the direction of the arrow 8 by a spring 4:. Between blocks 1, filament holders 2 are clamped, which hold the filament 5 at various points.

The small insulating blocks consist of quartz or the like and may be provided with borings, as shown inFigs. 2, 2, through which the guide rods are passed. Instead of one of the holes, projections and corresponding recesses, as shown in Figs. 3, 3, may be provided, so that only one guide rod 3 is required. Holes may be omitted altogether in the blocks, if the latter are provided with notches at the edge into which the guide rods engage. Figs. 4, 4 show, by way of example, an arrangement of that kind. The latter form is used as an example for building up the entire supporting column shown in Fig. 1.

In Figs. 5, 5 the insulating blocks 1 are provided with a hole, through which the guide rod 3 is passed, and with a projection and a corresponding recess as in Figs. 3, 3. They have, besides, notches at the edge into which the filament holder 2 can be laid, as

shown in the drawing. The one end of the filament holder is split, and the one part bent upward and the other downward.

According to Figs. 6, 6, in addition to the holes through which the guide rods are passed, two additional holes 9 and 10 are provided in which the bent ends of the filament holders engage.

Figs; 7 and 8 show a manner of fixing the filament holders, when small insulating blocks similar to those illustrated in Fig. 1 are used. Two notchesopposite to each other serve to accommodate the guide rods and two others to hold the filament holders. v The filament holders may also be clamped as illustrated in Figs. 8 and 9. Either the filament holders are made to be resilient themselves, or resilient discs are placed between the small insulating members. In Fig.9, the,

filament holders between the insulating blocks are not resilient themselves, but a force is exerted by the spring 4, which presses the blocks together in the direction shown by the arrow 8.

- .A particularly useful manner of carrying out the invention is shown in Figs. 10210", 10". According to this modification, the insulating blocks have six notches or recesses,

three'of which serve to take the guide rods and the others, situatedjbetween the first three, to accommodate the filament holders.

In these three figures the filament holders 2 are shown in three different oifset angular positions relative to one another, from which may be seen that with this form of insulating block a particularly uniform support of the filament can be obtained in which the intermediate supporting arms are well insulated.

The filament holders 2 are forked at their inner ends, the two ends of the fork of each arm being bent to engage always two'of the pertaining block notches, not engaged by vertical rods 3. The outer arm ends'holding the filament 5-may, as shown in the drawing, be bent to a vertical or-horizontal loop, the latter form being used when the filaments are to be conducted parallel to the axis of the support. The vertical loop form of the filament holder is used for filaments conducted round the support like a spiral, as in Fig. 1, particularly when the filament holder is shaped so as to give it a greater strength in the directions in'which it would be liable to bend. In that case, that end of the filament holder which holds the filament and which is twisted'through with respect-to the clamped part, is provided with a boring or the like.

Thethree plan views shown in Figs. 10*, 10", 10 may be regarded as three consecutive insulating members with filament holders in different positions. The filament holders are, of course, so made and forked that they cannot come into contact with the guide rods possibly carrying current, and so that it is impossible for a'leakage of current to take place.

The new support has the advantage that tensile and bending stresses in the insulating blocks are completely avoided, and that the insulating blocks are. stressed solely by compression. This is or particular importance with quartz, the tensile strength of quartz being, as is well known, very low.

Through the guide rods, the insulating blocks are protected against impermissibly large. movements sideways and against torsion. The spring holding the blocks together is in each case so chosen that no disturbance occurs at theinsul'ating blocks themselves.

The springin common toall insulating blocks,has shown in several modifications, may be substituted altogether or in partby resilientelements arranged between the insulating blocks, such as by making the por t-ions of the filament holders, clamped between the insulating blocks, resilient, such as is shown in Fig. 8, or by other equivalent means. Q The new support has the further advantage that by proportioning the filament holders suitably the conduction of heat to the'insulation blocks may beavoided. These blocks may, besides, by means of reflecting coverings formed by the guide elements, filament holders, parts forming springs or separate shells, be protected against radiant heat;

nection with the filament-feeding parts. Finally, by choosing the elastic forces of the mass and the frictional forces in'such a manner that the natural frequency of the whole system lies outside of the periodic forces which occur through the electrostatic stress, an efi'ective protection against mechanical vibrations may be obtained.- It is particularly noteworthy that with the new support the guide rods themselves can be made so elastic that they hold the insulating blocks lightly everywhere, so that rattling and shocks against the support, Wl11Cl1 would cause damage, cannotoccur.

The guide rods may either be solid, as shown in the drawing, or they may have the form of helical sprmgsso arranged for instance,

that each insulating block is held by one turn 31 of the helical spring. It is, for instance, advantageous to make the guide spring by stretching a helical spring shorter than the height of the column of blocks; theguide spirals mayalso be drawn over solid guide rods.

It is of particular value, to substitute the guide rods of the insulating members bya sheet-metal cover provided with grooves. This construction has the advantage that the insulating parts are electrostatically shielded, and, that besides, points and edges of the filament holders are covered, whereby the occurrenceof a gas discharge due to the high field strength is prevented. As a material for the sheet-metal covering, one having a high fusing point must be employed, molybdenum, tantalum or the like. The sheet metal is made as thin as possible to reduce the conduction of heat to the bottom end, where the connections for the current are made.

The spring pressing together the insulating members and the filament holders should be disposed very far from the cathode and the anode, in order that it should not become red hot and lose its resiliency.

We claim as our invention:

1. A supporting structure for an incandescent filament comprising a column composed of a plurality of individual blocks of insulating material, arms held between said blocks and having means at their outer ends for supporting the filament at several points between its ends, and means for resiliently supporting said blocks.

2. A supporting structure for an incandescent filament comprising a column composed of a plurality of individual blocks of insulating material, arms held between said blocks and having means at their outer ends for supporting the filament at several points between its ends, means for resiliently supporting said blocks and means for preventing said blocks from lateral displacement.

3. An incandescent filament support comprising a column composed of a plurality of individual blocks of insulating material and arms held between said blocks, having means for supporting the blocks resiliently upon one another, said arms having means at their outer ends for supporting the filament at several points between its ends.

4. A supporting structure for an incandescent filament, comprising a column composed of a plurality of individual blocks of insulating material, longitudinal guide means engaging said blocks for preventing their lateral shifting, arms held between said blocks and having means at their outer ends for supporting the filament at several points between its ends, and means for resiliently compressing said blocks.

5. A supporting structure for an incandescent filament, comprising a column composed of a plurality of individual blocks of insulating material, longitudinal guide rods extending through said blocks for holding them together and in alignment, arms held between 7 said blocks and having means at their outer ends for supporting the filament at several points between its ends, and means for resiliently compressing said blocks.

6. A supporting structure for an incandescent filament, comprising a column composed of a plurality of individual blocks of insulating material, a longitudinal guide rod extending through said blocks and correspondingly shaped projections and recesses in adjacent surfaces of said blocks, for holding said blocks together and in alignment, arms held between said blocks and having means at their outer ends for supporting the filament at several points between its ends, and means for resiliently compressing said blocks.

7. A supporting structure for an incandescent filament, comprising a column composed of a plurality of individual blocks of insulating material, each block being provided with a plurality of notches on its outer edge, longitudinal guide means engagin in some of said notches for aligning said looks into a column, arms held at their inner ends between adjacent blocks and engaging said blocks in notches other than those engaged by said guide means, said arms having a loop at their outer ends for supporting the filament at several points between its ends, and means for resiliently compressing said blocks.

8. A supporting structure for an incandescent filament, comprising a column composed of a plurality of individual blocks of insulating material, each block being provided with a plurality of notches on its outer edge, longitudinal guide means engaging in some of said notches for aligning said blocks into a column, arms held at their inner ends between adjacent blocks and having their inner ends forked and bent to engage in several block notches other than those engaged by said guide means, said arms having a loop at their outer ends for supporting the filament at several points between its ends, and means for resiliently compressing said blocks.

9. A supporting structure for a helically wound incandescent filament, comprising a column disposed in the axis of helix and being composed of a plurality of individual blocks of insulating material, each block being provided with a plurality of notches on its outer edge, longitudinal metallic guides engaging in some of said notches for aligning said blocks into a column, and for conducting the current to one end of said filament, arms held at their inner ends between at least some of said blocks and having their inner ends forked and bent to engagein several block notches other than those engaged by said metallic guides, said arms having a filament supporting loop at their free ends and being ofi'set at an angle relatively to one another for supporting the filament helix at a plurality of points intermediate its ends, and means for conducting current to the other filament end.

In testimony whereof we afiix our signatures.

RUDOLF GOTTFRIED BERTHOLD.

WALTER STOCKMEYER. 

